Find donor calls in Chorus that never became DonorPerfect contacts

**Objective:** Find Chorus conversations with DonorPerfect donors from the last `{lookback-days}` days (default 30) that were never logged as a DonorPerfect contact, optionally limited to conversations owned by the Chorus user `{user-email}`.

**Step 1: Conversations in Chorus**

Call `chorus-get-engagements` with date.from set to the start of the window, max-records 100, and user-email set to `{user-email}` if it is given. If 100 come back, say the list was capped.

For each conversation, call `chorus-get-conversation-participants` with its conversation-id and keep the external participants (skip those whose type marks them internal or that have a user-id).

**Step 2: Match to donors and check the contact log**

For each distinct external email, call `donorperfect-get-donor` with it as email. For each matched donor, call `donorperfect-get-contact` with the donor-id and contact-date.from and contact-date.to set to two days either side of the conversation date.

A conversation-donor pair is logged if any contact falls in that range, unlogged if none does.

**Step 3: Report**

* Table of unlogged pairs: conversation date, subject, Chorus owner (user-name), conversation-id, donor-id, donor name.
* Count of logged pairs.
* Count of external participants who are not DonorPerfect donors, grouped by company-name.

End by noting that each unlogged row can be logged with the `log-conversation-as-donor-contact` prompt.

**Rules & Guidelines:**

* Tools named donorperfect-... are on the donorperfect server. Tools named chorus-... are on the chorus server.
* This prompt is read-only. Do NOT call any DonorPerfect write tool (`donorperfect-save-donor`, `donorperfect-save-contact`, `donorperfect-save-gift`, `donorperfect-save-pledge`, `donorperfect-save-address`, `donorperfect-save-other-info`, `donorperfect-save-link`, `donorperfect-set-flag`) or any Chorus write tool (`chorus-add-moment`, `chorus-add-playlist-moment`, `chorus-create-playlist`, `chorus-update-moment`, `chorus-update-playlist`, `chorus-update-playlist-moment`, `chorus-export-recordings`, `chorus-export-scorecards`).
* Match on email only, case-insensitively.

**Validation:**

* If Chorus returns no conversations in the window, say so and stop.
* If no participant matches a donor, report that none of the conversations involved a DonorPerfect donor.
* If an email matches more than one donor, list it as ambiguous rather than choosing one.